Completion of the new Highway 99 tunnel, originally planned for late 2015, has been delayed even further, possibly until 2019. It is now estimated that the project will be over budget by $223 million. Unfortunately, it may be the taxpayers who end up paying the cost through Washington state's gas tax, tolls, and increased debt of the state transportation fund.
When finished, the tunnel will stretch 1.7 miles and span 4 lanes of traffic. It is being built to replace the outdated viaduct which could be seriously compromised in the event of seismic activity. The total estimated cost of the project has now reached $3.374 billion.
The tunnel is being excavated using Bertha, a 57-foot diameter tunnel boring machine. A large portion of the delay was caused by Bertha breaking down approximately one third of the way through the boring distance. The machine sat idle for over two years as workers had to excavate down near Pioneer Square to repair it after a major malfunction. The prime contractor, Seattle Tunnel Partners (STP), blames an 8-inch steel pipe left over from state groundwater testing for the breakdown, however the state believes this is unlikely. Now that it has been repaired, Bertha is tunneling at a rate of 40 feet per day.
Source: The Seattle Times
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